Master Degree / Yüksek Lisans Tezleri
Permanent URI for this collectionhttps://hdl.handle.net/11147/3008
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Master Thesis Design of Ni-Metal Organic Framework (ni-Mof(74)) for Efficient Co2 Adsorption(01. Izmir Institute of Technology, 2024) Gürsel Karpuz, Hande; Özkan, Seher Fehime Çakıcıoğlu; 01. Izmir Institute of TechnologyThe urgency the address high CO2 concentrations in the Earth's atmosphere increases each day prompting collaborative efforts between industry and the science community to develop various solutions. Among these, carbon capture utilization and storage (CCUS) technologies are proven to be integral. Rooted in CO2 adsorption, carbon capture forms the cornerstone of CCUS technologies. Consequently, developing effective CO2 capture materials and designing systems capable of integrating these materials into real-world practical applications play a crucial role. In this study, one of the most promising materials for future CO2 capture technologies, Ni-MOF-74, is synthesized, characterized, and tested for CO2 adsorption capacity. Following the synthesis process Ni-MOF-74 is immobilized on acrylonitrile fabric in order to achieve a flexible and versatile structure with high CO2 capacity that can be integrated in various applications. The highest surface area and CO2 adsorption capacity achieved by the synthesized Ni-MOF-74 powder are 180 m2/g and 1.98 mmol/g, respectively. Synthesized Ni-MOF-74 powder was successfully immobilized on an acrylic fabric substrate through the drip casting method. The resulting composite showed a decrease in CO2 adsorption capacity only by 8% which is promising for practical applications and a fair compromise considering that the flexible structure offers an opportunity to be utilized in a wide range of scenarios.Master Thesis Mechanistic Investigation of Carbon Dioxide Hydrogenation on Bimetallic Iron-Cobalt Surfaces by Density Functional Theory(2023) Kızılkaya, Ali Can; Kızılkaya, Ali Can; 03.02. Department of Chemical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyKüresel CO2 emisyonundaki artışa bağlı olarak iklim değişikliği, yalnızca CO2 üretiminin azaltılmasındaki önemi artırmakla kalmadı, aynı zamanda katalitik CO2 dönüşümü yoluyla kimyasalların ve yakıtların üretiminde kullanılmasının önemini de artırdı. Aktif ve seçici katalizörlerin rasyonel tasarımı, bu proseslerin endüstriyel uygulamalarına yönelik kritik öneme sahiptir. Bu tezde, C1 hidrokarbonların üretimi için CO2 hidrojenasyonunun mekanizmasını araştırmak ve FeCo bimetalik katalizörlerin (111) yüzeyindeki yapı-aktivite ilişkisinin atomik düzeyde anlaşılmasını sağlamak ve tasarıma rehberlik etmek için ilk prensiplere dayalı hesaplamalı bir çalışma yapıldı. Bu tezde, fcc-Co(111) ve Fe-katkılı Co(111) [FeCo(111)] yüzeyleri üzerinde CO2 hidrojenasyonunun C1 hidrokarbonlara verdiği temel reaksiyonların kinetiği, yoğunluk fonksiyonel teorisi (YFT) kullanılarak karşılaştırıldı. Araştırmamız Fe'nin Co(111) yüzeyine eklenmesi ile birlikte, CO2 aktivasyonunu desteklemesine rağmen genel reaksiyon hızını hafifçe azalttığını ortaya çıkardı. 1 ML Fe-katkılı Co(111) yüzeyinin daha düşük atomik H kapsamaları ve daha yüksek aktivasyon bariyerleri nedeniyle hidrojenasyon reaksiyonlarını engellemesi Fe'nin Lewis bazik karakterine atfedilmiştir. Fe'in katılması temel olarak kobalt yüzeylerinden oksijenin ayrılmasını engellemektedir. Bu nedenle, Fe katkısının, CO2 hidrojenasyonu sırasında bimetalik FeCo katalizörleri üzerinde oksidik fazların oluşumunu teşvik etmesi beklenmektedir.Master Thesis Investigation of Electrochemical Co2 Capture System(Izmir Institute of Technology, 2022) Uzunlar, Erdal; Uzunlar, Erdal; 03.02. Department of Chemical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyFossil fuels have been used as a primary energy source for many years to meet the increasing energy demand since the industrial revolution. Fossil fuels are an important source of carbon that triggers global warming and climate change. To reduce the accumulation of carbon dioxide in the atmosphere, carbon capture has become more important. Conventional carbon capture technology is a thermally regenerated amine-based capture based on monoethanolamine (MEA). In this process, carbon dioxide is captured in an absorption column with the amine solution, and CO2-amine solution is sent to the stripping column, where the solution is heated to release the captured CO2 and regenerate the amine solution. However, an important disadvantage of this process is that it requires high energy for the CO2 release step. Recently, electrochemical CO2 capture process is proposed in the literature to decrease the energy requirement. The aim of this study is to investigate the electrochemical CO2 capture process using homopiperazine (HPZ). Unlike the conventional CO2 capture process, the CO2 release step is performed using an electrochemical cell. In the anode compartment of this electrochemical cell, the formed CO2-amine complexes are converted into amine-metal complexes from which the CO2 is released. The amine-metal complexes are then sent to the cathode, where the complex decomposes and metal deposition occurs. Laboratory-scale studies of the electrochemical capture process using MEA and HPZ as solvent were carried out. In the obtained results, it was found that HPZ has higher CO2 capture capacity and CO2 release rate than MEA and a similar CO2 absorption rate as MEA. In addition, UV-Vis spectra analyses showed that the reaction rate at the anode was much higher than the reaction rate at the cathode for both amines.Master Thesis Renewable natural gas production via Sabatier reaction(01. Izmir Institute of Technology, 2021) Çamlık, Cansu; Şeker, Erol; Şeker, Erol; 01. Izmir Institute of Technology; 03.02. Department of Chemical Engineering; 03. Faculty of EngineeringThis study attempts to understand the effect of support basicity on Sabatier reaction and improve the performance of Ni based catalysts by introducing calcium which is known for its basicity. In accordance with this purpose, Ni-Al2O3-CaO catalysts were synthesized with modified sol-gel method. Effect of Ni loading, calcination temperature and calcium content were investigated. Al2O3-CaO supports were synthesized at three ratios as follows; 70-30 wt.%, 40-60 wt.%, 10-90 wt.% wherein Ni/Al2O3 catalyst was used as reference catalyst. Based on thermodynamic analysis, reaction was conducted at 400oC and 1 atm with inlet composition of CO2/H2=1/4 and total volumetric flow rate of 100 ml/min. Reference catalyst calcined at 700oC was found to be inactive at used reaction conditions due to the presence of inactive NiAl2O4 phase. Increasing Ni loading from 1 wt.% to 10 wt.% increased both CO2 conversion and methane selectivity. Over the catalysts calcined at the temperature of 900oC, maximum methane yield was obtained over 10Ni-70Al-30Ca-900 as 8%. The influence of Ni loading was more pronounced for catalysts calcined at 700oC. In 10Ni-70Al-30Ca-700 catalyst, NiO particles were smaller than 5 nm. Therefore, it is conceivable that the alumina-calcium mixed oxide support could disperse higher loadings of Ni, which could result in higher CO2 conversion. Ca modification was found to have a prominent impact on both methane selectivity and yield. With 10Ni-10Al-90Ca-700, being best performing catalyst, CO2 conversion obtained as 76% and methane yield was 60%. The promotion of catalytic performance might arise from intensifying the CO2 chemisorption supported by XRD and TGA results.Master Thesis Electrolyte-Based Simulations of a Laboratory Scale Carbon Dioxide Capture Process(01. Izmir Institute of Technology, 2020) Özdamar, Ateş Batıkan; Uzunlar, Erdal; Özdamar, Ateş Batıkan; Uzunlar, Erdal; 01. Izmir Institute of Technology; 03.02. Department of Chemical Engineering; 03. Faculty of EngineeringThe aim of this thesis is to design and simulate a laboratory-scale CO2 capture system on Aspen Plus. The studied CO2 capture process is a post-combustion CO2 capture process. The commonly employed monoethanolamine (MEA) sorbent is compared with the piperazine (PZ) sorbent in terms of reaction kinetics and energy consumption throughout the study. Three main simulation studies were performed in order to compare MEA and PZ sorbents. First, an absorption column, then an open loop (single pass) process and finally a closed loop (recycle) process were designed and simulated on Aspen Plus. The simulations were carried out at various inlet gas pressures. After designing an absorber column, CO2 loading, temperature, pressure, mole flow, packing details, column height and diameter constraints were determined. As a result of open loop and closed loop processes, the column operations in absorber and stripper columns regarding CO2 reactions and energy consumption were investigated. The results showed that PZ absorbs and releases more CO2, has a faster kinetics, and is more energy efficient compared to MEA in CO2 capture processes.Master Thesis Carbon Dioxide Hydrogenation on Alumina Supported Ruthenium Catalysts(Izmir Institute of Technology, 2019) Hamza, Gökmen Oğuzcan; Şeker, Erol; Şeker, Erol; 03.02. Department of Chemical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyIn this study the effect of basicity of catalyst is investigated using different metal oxide supported Nickel and Ruthenium catalyst. The basic strength of catalysts was orchestrated with using different types of metals and different composition of supports. In this study Al2O3-CaO, Al2O3-MgO, Al2O3-BaO supports were used with nickel and ruthenium catalyst, which synthesized with sol-gel method. Different mass ratios of supports were used such as; 100%, 70%/30%, %50/50%, 20%/80% respectively. For all metal oxides Nickel loadings are 1 %, 5% and Ruthenium loading is 0.5%. Calcination temperature was 500 0C with 6 hours. All catalysts were used in methanation reaction with conditions varies between 300-600 0C, inlet ratio of CO2/H2 1/4 to 1/6 and GSHV 5000h-1/10000h-1. The products were analyzed using GC and catalysts were analyzed using XRD NH3-TPD and BET. Nickel load selected as 1%, magnesium supported catalysts' the main crystallites were aluminum oxide and magnesium oxide for 30%,50%,80; respectively. Calcium supported catalyst had had alumina and calcium oxide crystallites for 30%,50% respectively. Barium supported catalysts had had alumina and barium mix oxide crystallites for 30%,50% respectively. For 5% Nickel loaded 70-30% alumina magnesia mix oxide catalyst magnesia and alumina crystallites are found. Aluminum magnesium mix oxide catalysts had higher basicity than aluminum barium mix oxide catalysts for 1% nickel catalysts. Ruthenium based magnesium alumina mix oxide catalyst had higher basicity than nickel-based magnesium alumina catalysts. Ruthenium catalysts had higher total performance towards both of the reverse water gas shift reaction and carbon dioxide methanation than nickel-based catalysts.Master Thesis Enztmatic Co2 Sequestration by Carbonic Anhydrase(Izmir Institute of Technology, 2008) Kanbar, Bora; Özdemir, Ekrem; Özdemir, Ekrem; 03.02. Department of Chemical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyCarbonic Anhydrase (CA) was immobilized within Polyurethane (PU) Foam and characterized for CO2 sequestration purposes. The catalytic activities for the free and immobilized CA were estimated by using p-Nitrophenyl Acetate (p-NPA) as the substrate. The activities were estimated in tris buffer containing 10% Acetonitrile.Because, the p-NPA is only soluble up to 4mM in aqueous phase. Lineweaver-Burk relationship was employed to estimate the Michaelis-Menten kinetic parameters for the free and immobilized CA. The kcat, KM, and kcat/KM values for free enzyme were found to be 1.21s-1, 12.2mM, and 148.1M-1s-1, respectively. The KM value for immobilized BCA was estimated to be 9.59mM in tris buffer (50mM, pH.7.5), in the presence of 10% acetonitrile at the same conditions. The immobilized CA was stable and did not loose any activity over seven consecutive washings and activity tests. In addition, while the free CA lost its activity in 45 days stored at 4oC in fridge, the immobilized CA was stable and did not loose any activity over 45 day period. The optimum temperature for the immobilized BCA was found to be between 35oC and 45oC. No activity was observed for the immobilized CA at 60oC. Thermal deactivation energies for the free and immobilized CA were found to be 29kcal/mol and 86kcal/mol, respectively. The immobilized CA was employed in CaCO3 precipitation. It was found that the CaCO3 particles were less than 100nm and more evenly dispersed. It was concluded that the immobilized CA could be used in CO2 sequestration.